Preheat oven to 425°F. In large bowl, combine olive oil, Italian seasoning, garlic, salt, and pepper. Add potatoes and toss to coat; spread evenly in an ungreased 15” x 10” baking pan. Cover tightly with foil. Bake 35 to 40 minutes or until tender.
Let cool 15 minutes. Reduce oven temperature to 350°F.
In large skillet, brown lean ground beef with onion and seasonings; drain well. Add spaghetti sauce and simmer on low.
Combine drained spinach and ricotta cheese; mix well.
Arrange a third of the potatoes evenly in a greased 9” x 13” baking dish. Layer with half the spinach mixture, one-third the lean ground beef, and one-third of the mozzarella. Repeat next layer with half the spinach mixture, one-third the lean ground beef, and one-third of the mozzarella. Top with remaining potatoes, meat sauce and mozzarella; sprinkle with Parmesan cheese.
Bake uncovered for 35 to 40 minutes until bubbly. Let stand 5 minutes before serving.